U.S. patent application number 17/193896 was filed with the patent office on 2021-07-01 for hypotonic hydrogel formulations for enhanced transport of active agents at mucosal surfaces.
The applicant listed for this patent is The Johns Hopkins University. Invention is credited to Abhijit Date, Laura Ensign, Justin Hanes, Yoo Chun Kim.
Application Number | 20210196837 17/193896 |
Document ID | / |
Family ID | 1000005473899 |
Filed Date | 2021-07-01 |
United States Patent
Application |
20210196837 |
Kind Code |
A1 |
Ensign; Laura ; et
al. |
July 1, 2021 |
HYPOTONIC HYDROGEL FORMULATIONS FOR ENHANCED TRANSPORT OF ACTIVE
AGENTS AT MUCOSAL SURFACES
Abstract
Hypotonic gelling vehicles are used as solubilizing agents for
drugs and as a means to provide sustained drug delivery to a
mucosal tissue. Solubilizing drugs at higher concentrations
enhances drug penetration into the tissues of the body, while the
hypotonic gelling vehicle further improves distribution of the drug
over a larger surface area for increased absorption and sustained
release for reduced side effects and longer duration of action.
Inventors: |
Ensign; Laura; (Towson,
MD) ; Hanes; Justin; (Baltimore, MD) ; Date;
Abhijit; (Baltimore, MD) ; Kim; Yoo Chun;
(Odenton, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Johns Hopkins University |
Baltimore |
MD |
US |
|
|
Family ID: |
1000005473899 |
Appl. No.: |
17/193896 |
Filed: |
March 5, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16770792 |
Jun 8, 2020 |
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PCT/US2018/064441 |
Dec 7, 2018 |
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17193896 |
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62596578 |
Dec 8, 2017 |
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62627559 |
Feb 7, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 31/404 20130101;
A61K 9/08 20130101; A61K 31/473 20130101; A61K 9/0048 20130101;
A61P 27/02 20180101; A61K 47/6903 20170801; A61K 47/34
20130101 |
International
Class: |
A61K 47/69 20060101
A61K047/69; A61K 9/00 20060101 A61K009/00; A61K 9/08 20060101
A61K009/08; A61K 31/404 20060101 A61K031/404; A61K 31/473 20060101
A61K031/473 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with government support under Grant
No. RO1DK107806 awarded by the National Institutes of Health. The
government has certain rights in the invention.
Claims
1. A method for treating an eye disease comprising administering to
the eye once a week or less frequently a formulation comprising a
therapeutic, prophylactic, nutraceutical, or diagnostic agent, a
gel-forming polymer for application to the eye, formulated so that
it is at a concentration below the critical gel concentration (CGC)
of the polymer under isotonic conditions at a temperature between
about 25 to about 37.degree. C., and excipients to form a
pharmaceutically acceptable hypotonic formulation of the polymer
suitable for delivery to the eye of an individual in need
thereof.
2. The method of claim 1, wherein the formulation is in dry or
freeze-dried form.
3. The method of claim 1, wherein the gel-forming polymer is a
thermosensitive gel-forming polymer.
4. The method of claim 3, wherein the thermosensitive gel-forming
polymer has a critical solution temperature that is below
30.degree. C.
5. The method of claim 1, wherein the polymer is a poloxamer.
6. The method of claim 1, wherein the polymer in combination with
the excipient forms a gel on administration into or onto the
eye.
7. (canceled)
8. The method of claim 1, wherein the agent is water-soluble.
9. The method of claim 1, wherein the agent is poorly
water-soluble.
10. The method of claim 1, wherein the formulation releases the
therapeutic, prophylactic, or diagnostic agent into or onto the eye
over a period of at least one week.
11. (canceled)
12. The method of claim 1, wherein the gel-forming polymer is
between greater than 12% and less than 24% F98 in an aqueous
excipient.
13. The method of claim 1, wherein the gel-forming polymer is
between 10 and 18% polaxamer F127.
14. The method of claim 1, wherein the gel-forming polymer forms a
uniformly thick layer at the time of administration onto the ocular
surface.
15. The method of claim 1, for administration in the form of a gel
or liquid.
16. The method of claim 15, wherein the formulation is provided in
a single or multiple dosage unit for administration.
17. The method of claim 1, wherein the agent is a protein or
peptide, small molecule, sugar or polysaccharide, lipid,
glycolipid, glycoprotein, nucleic acid, oligomer or polymer
thereof, or small molecule.
18. The method of claim 1, wherein the agent is selected from the
group consisting of steroids, glaucoma agents, tyrosine kinase
inhibitors, immunosuppressive agents, anti-fibrotic agents,
anti-infectives, hormones and chemotherapeutic agents.
19-20. (canceled)
21. The method of claim 1, wherein the formulation is in the form
of an eye drop.
22. The method of claim 1, wherein the therapeutic agent is
sunitinib malate or acriflavine.
Description
CROSS-REFERENCED TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
Provisional Application No. 62/596,578 filed Dec. 8, 2017 and U.S.
Provisional Application No. 62/627,559 filed Feb. 7, 2018, which
are hereby incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0003] This invention is generally in the field of formulations for
enhanced drug delivery, in particular drug delivery at mucosal
surfaces.
BACKGROUND OF THE INVENTION
[0004] The mucosa is a membrane that lines various cavities in the
body, e.g., mouth, gut, uterus, vagina, colon, anal canal, trachea,
lungs, bladder, etc. As used herein, skin may be considered a
mucosal surface. The mucosa consists of the epithelium itself and
also the supporting loose connective tissue, called lamina propria,
immediately beneath the epithelium. Deeper connective tissue which
supports the mucosa is called the submucosa. In the GI tract, there
is a thin layer of smooth muscle, the muscularis mucosae, at the
boundary between mucosa and submucosa.
[0005] The mucosal surfaces of the body are selectively permeable.
Mucosal barrier injuries, such as oral and gastrointestinal
mucositis, are a common complication following cytoreductive cancer
therapy and radiotherapy (Sonis et al., Cancer Supplement,
100(9):1995-2023, 2004). Some capsid viruses can diffuse through
mucus as rapidly as through water and thereby penetrate to the
epithelium even though they have to diffuse `upstream` through
mucus that is being continuously secreted. These viruses are
smaller than the mucus mesh spacing, and have surfaces that do not
stick to mucus (Cone R. A., Adv. Drug Deliv Rev, 61(2):75-85,
2009). For example, women are disproportionately infected with HIV,
partly owing to a lack of female-controlled prevention methods
(Ndesendo et al., AAPS PharmSciTech, 9:505-520, 2008). An easily
administered, discreet, and effective method for protecting women
against vaginal HIV transmission could prevent millions of
infections worldwide. However, vaginal folds, or "rugae", that
accommodate expansion during intercourse and childbirth, are
typically collapsed by intra-abdominal pressure, making the
surfaces of these folds less accessible to drugs and drug carriers
(Alexander et al., Sex Transm Dis, 29:655-664, 2004). Poor
distribution into the vaginal folds, even after simulated
intercourse, has been cited as a critical factor for failure to
protect susceptible vaginal surfaces from infection. Distribution
over the entire susceptible target surface has been proven to be
important for preventing and treating infections. Additionally, to
increase user acceptability, drug delivered to the vagina should be
retained in the vaginal tract at effective concentrations over
extended periods of time.
[0006] Achieving sustained local drug concentrations is challenging
because the vaginal epithelium is highly permeable to small
molecules and also because soluble drug dosage forms (gels, creams)
can be expelled by intra-abdominal pressure and ambulation. Lastly,
drug delivery methods must be safe and non-toxic to the vaginal
epithelium. Improvements in the distribution, retention, and safety
profile of vaginal dosage forms may lead to a substantial increase
in efficacy and decrease in the side effects caused by largely
ineffective systemic treatments for cervicovaginal infections and
diseases (Thigpen T. Cancer J. 9:245-432, 2003; Robinson et al.,
Obstet Gynecol, 99:777-784, 2002).
[0007] Sustained drug delivery to the mucosal surfaces of the body
has potential for improving the treatment and prevention of many
diseases, including sexually transmitted infections, inflammatory
bowel disease, lung inflammation, and degenerative eye conditions
to name only a few. Achieving sustained prophylactic or therapeutic
drug concentrations using traditional soluble dosage forms remains
challenging due to degradation, rapid shedding, and rapid systemic
absorption of drug. There is an urgent need for compositions for
delivery to mucosal surfaces that provide a physical barrier to
pathogen entry. Also, there is an unmet need for compositions for
mucosal delivery that offer retention and sustained release of
prophylactic, therapeutic or diagnostic agents at mucosal
surfaces.
[0008] Therefore, it is an object of the invention to provide
improved compositions for delivery of active agents with greater
efficacy and safety to mucosal surfaces that act as barriers to
pathogen transport into the mucosa.
[0009] It is a further object of the present invention to provide
improved compositions for delivery to mucosal surfaces that allow
retention and sustained release of prophylactic, therapeutic or
diagnostic agents at mucosal surfaces.
[0010] It is still a further object of the present invention to
provide methods of making the improved compositions for delivery to
mucosal surfaces.
SUMMARY OF THE INVENTION
[0011] Hypotonic gelling vehicles are used as solubilizing agents
for drugs with lower water solubility. This approach is in contrast
to using a nanoparticle or nanocrystal to improve the
solubility/dissolution of a hydrophobic drug. Solubilizing the
drugs enhances mucosal penetration, while the hypotonic gelling
vehicle further improves distribution and penetration. Many drugs
have minimal water solubility, limiting their delivery to mucosal
surfaces.
[0012] Solubilizing drugs in thermosensitive gelling vehicles
improves distribution, retention, and penetration of drugs
delivered topically when administered hypotonically. Hypotonic
formulations of hydrogel forming polymers, preferably poloxamers
(nonionic triblock copolymers composed of a central hydrophobic
chain of polyoxypropylene such as poly(propylene oxide) flanked by
two hydrophilic chains of polyoxyethylene such as poly(ethylene
oxide)), have been developed for enhanced delivery of therapeutic,
diagnostic, prophylactic or other agents, to epithelial tissues,
especially those having a mucosal coating. The polymers are
administered in a hypotonic solution at a concentration less than
their normal critical gelling concentration (CGC). Typically, a
Poloxamer gel administered into the vagina or colorectum at its CGC
will form a "plug" of gel in the lumen. In contrast, fluid from a
hypotonically-administered Poloxamer solution below the CGC will be
absorbed by the epithelial surface, drawing the Poloxamer into the
mucus layers and up against the epithelium where it then becomes
concentrated enough to gel, thereby enhancing and facilitating
delivery of agents to the epithelial cells. As the Poloxamer is
concentrated at the tissue/mucosal interface, it mixes with mucus
and gels up against the epithelial surface. The endogenous mucin
glycopolymers affect the gelling properties of the hypotonic
gelling agents, including the concentration of gelling agent needed
to gel and the pore structure of the resulting gel/mucin mixture.
The hypotonic gelling vehicles coat the epithelium, including the
folds, after vaginal and colorectal application.
[0013] Studies demonstrate the advantages of these hypotonic
polymeric gel formulations for drug delivery, especially through
mucosal epithelia.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a scheme for solubilization of hydrophobic drugs
(e.g. cyclosporine A or budesonide) by a solvent evaporation
method.
[0015] FIG. 2 is a scheme for solubilization of hydrophobic drugs
(e.g. moxifloxacin) by a bead milling method.
[0016] FIG. 3 is a scheme for solubilization of hydrophobic drugs
(e.g. cyclosporine A or brimonidine) by a dialysis method.
[0017] FIG. 4 is scheme for solubilization of hydrophobic drugs
(e.g. brinzolamide) by a solvent evaporation method.
[0018] FIG. 5A is a graph showing the effect of various
concentrations of Pluronic F127 (10%, 12%, 15%, and 18%) on the
cumulative increase in tear production induced by cyclosporine in
healthy rabbit eyes for 12 h after a single drop. FIG. 5B is a
graph of the tear production in the healthy rabbit eye 10 h after
each of 5 daily doses of gelCsA, the gel vehicle containing no
drugs (gelCsA Vehicle), Restasis, the Restasis vehicle (Endura), or
no treatment (Untreated). FIGS. 5C and 5D are line graphs showing
concentrations of cyclosporine in rat cornea (FIG. 5C) and
conjunctiva (FIG. 5D) tissue after administering cyclosporine eye
drops formulated as gelCsA (Hypotonic), gelCsA (Isotonic), gelCsA
(Conventional), or Restasis over the period of 8 hours.
[0019] FIGS. 6A and 6B are line graphs showing changes in
intraocular pressure as a function of time in hours with different
treatments. FIG. 6A a graph showing changes over the period of 8
hours in intraocular pressure when treated with gelBRZ formulated
as either a conventional (18% F127) gelling material, or at the
lower concentration (12% F127) formulated as either hypotonic or
isotonic. FIG. 6B is a graph showing changes in intraocular
pressure when treated with hypotonic gelBRZ formulation, a
commercial eye drop, AZOPT.RTM., or gelBRZ vehicle over the period
of 8 hours.
[0020] FIG. 7A is a bar graph showing the cumulative change in IOP
over 8 h after administration of brimonidine tartrate 0.15% in 10%,
12%, 15%, and 18% F127 (gelBT). FIG. 7B is a line graph showing
changes in intraocular pressure when treated with hypotonic gelBT
formulation, isotonic gelBT (12% F127), or conventional gelBT (18%
F127) in normotensive rabbits over a 10-hour period. FIG. 7C is a
line graph showing changes in intraocular pressure when treated
with hypotonic gelBT formulation, the commercial 0.15% brimonidine
tartrate eye drop (ALPHAGAN.RTM.), or gelBT vehicle over the period
of 10 hours. FIGS. 7D-7F show brimonidine levels in cornea (FIG.
7D), conjunctiva (FIG. 7E), and aqueous (FIG. 7F) from rats 1, 4,
and 8 hr after the last dose (dosing 2.times. daily for 5 days).
FIG. 7G is a line graph showing changes in intraocular pressure
when treated with a mild hypotonicity (gelBT 200 mOsm) or hypotonic
gelBT.
[0021] FIG. 8A is a bar graph showing the viscosity under low/no
shear of a standard lubricating eye drop (GENTEAL.RTM.), 16% F127,
and 16% F127 with 0.5% HPMC. FIG. 8B shows that the shear thinning
properties (decrease in viscosity when placed under shear) for
GENTEAL.RTM.), 16% F127, and 16% F127 with 0.5% HPMC.
[0022] FIGS. 9A and 9B are histograms showing concentration of
sunitinib or N-desethyl sunitinib in various ocular tissues and
fluids in dutch belted rabbits following daily topical dosing with
sunitinib malate in the hypotonic gelling vehicle (gelSUN) for 14
days (FIG. 13A), and in farm pigs following daily topical dosing
with sunitinib malate in the hypotonic gelling vehicle (gelSUN) for
5 days.
DETAILED DESCRIPTION OF THE INVENTION
I. Definitions
[0023] As generally used herein "pharmaceutically acceptable"
refers to those compounds, materials, compositions, and/or dosage
forms which are, within the scope of sound medical judgment,
suitable for use in contact with the tissues of human beings and
animals without excessive toxicity, irritation, allergic response,
or other problems or complications commensurate with a reasonable
benefit/risk ratio.
[0024] "Biocompatible" and "biologically compatible", as used
herein, generally refer to materials that are, along with any
metabolites or degradation products thereof, generally non-toxic to
the recipient, and do not cause any significant adverse effects to
the recipient. Generally speaking, biocompatible materials are
materials which do not elicit a significant inflammatory, immune or
toxic response when administered to an individual.
[0025] The terms "gel" and "hydrogel", as used herein, refers to a
swollen, water-containing network of finely-dispersed polymer
chains that are water-insoluble, where the polymeric molecules are
in the external or dispersion phase and water (or an aqueous
solution) forms the internal or dispersed phase. The chains can be
chemically crosslinked (chemical gels) or physically crosslinked
(physical gels). Chemical gels possess polymer chains that are
connected through covalent bonds, whereas physical gels have
polymer chains linked by non-covalent bonds or cohesion forces,
such as Van der Waals interactions, ionic interaction, hydrogen
bonding, or hydrophobic interaction.
[0026] The polymer chains are typically hydrophilic or contain
hydrophilic polymer blocks. "Gel-forming polymers" is used to
describe any biocompatible polymer, including homopolymers,
copolymers, and combinations thereof, capable of forming a physical
hydrogel in an aqueous medium when present at or above the critical
gel concentration (CGC).
[0027] The "critical gel concentration", or "CGC", as used herein,
refers to the minimum concentration of gel-forming polymer needed
for gel formation, e.g. at which a solution-to-gel (sol-gel)
transition occurs. The critical gel concentration can be dependent
on a number of factors, including the specific polymer composition,
molecular weight, temperature, and/or the presence of other
polymers or excipients.
[0028] The term "thermosensitive gel-forming polymer" refers to a
gel-forming polymer that exhibits one or more property changes with
a change in the temperature. For example, some thermosensitive
gel-forming polymers are water soluble below a certain temperature
but become water insoluble as temperature is increased. The term
"lower critical solution temperature (LCST)" refers to a
temperature, below which a gel-forming polymer and solvent are
completely miscible and form a single phase. For example, "the LCST
of a polymer solution" means that the polymer is uniformly
dispersed in a solution at that temperature (i.e., LCST) or lower,
but aggregates and forms a second phase when the solution
temperature is increased beyond the LCST.
[0029] "Hydrophilic," as used herein, refers to molecules which
have a greater affinity for, and thus solubility in, water as
compared to organic solvents. The hydrophilicity of a compound can
be quantified by measuring its partition coefficient between water
(or a buffered aqueous solution) and a water-immiscible organic
solvent, such as octanol, ethyl acetate, methylene chloride, or
methyl tert-butyl ether. If after equilibration a greater
concentration of the compound is present in the water than in the
organic solvent, then the compound is considered hydrophilic.
[0030] "Hydrophobic," as used herein, refers to molecules which
have a greater affinity for, and thus solubility in, organic
solvents as compared to water. The hydrophobicity of a compound can
be quantified by measuring its partition coefficient between water
(or a buffered aqueous solution) and a water-immiscible organic
solvent, such as octanol, ethyl acetate, methylene chloride, or
methyl tert-butyl ether. If after equilibration a greater
concentration of the compound is present in the organic solvent
than in the water, then the compound is considered hydrophobic.
[0031] As used herein, the term "treating" includes inhibiting,
alleviating, preventing or eliminating one or more symptoms or side
effects associated with the disease, condition, or disorder being
treated.
[0032] The term "reduce", "inhibit", "alleviate" or "decrease" are
used relative to a control, either no other treatment or treatment
with a known degree of efficacy. One of skill in the art would
readily identify the appropriate control to use for each
experiment. For example a decreased response in a subject or cell
treated with a compound is compared to a response in subject or
cell that is not treated with the compound.
[0033] As used herein the term "effective amount" or
"therapeutically effective amount" means a dosage sufficient to
treat, inhibit, or alleviate one or more symptoms of a disease
state being treated or to otherwise provide a desired pharmacologic
and/or physiologic effect. The precise dosage will vary according
to a variety of factors such as subject-dependent variables (e.g.,
age, immune system health, etc.), the disease or disorder, and the
treatment being administered. The effect of the effective amount
can be relative to a control. Such controls are known in the art
and discussed herein, and can be, for example the condition of the
subject prior to or in the absence of administration of the drug,
or drug combination, or in the case of drug combinations, the
effect of the combination can be compared to the effect of
administration of only one of the drugs.
[0034] "Excipient" is used herein to include a compound that is not
a therapeutically or biologically active compound. As such, an
excipient should be pharmaceutically or biologically acceptable or
relevant, for example, an excipient should generally be non-toxic
to the subject. "Excipient" includes a single such compound and is
also intended to include a plurality of compounds.
[0035] The term "osmolarity", as generally used herein, refers to
the total number of dissolved components per liter. Osmolarity is
similar to molarity but includes the total number of moles of
dissolved species in solution. An osmolarity of 1 Osm/L means there
is 1 mole of dissolved components per L of solution. Some solutes,
such as ionic solutes that dissociate in solution, will contribute
more than 1 mole of dissolved components per mole of solute in the
solution. For example, NaCl dissociates into Na and in solution and
thus provides 2 moles of dissolved components per 1 mole of
dissolved NaCl in solution. Physiological osmolarity is typically
in the range of about 280 to about 310 mOsm/L.
[0036] The term "tonicity", as generally used herein, refers to the
osmotic pressure gradient resulting from the separation of two
solutions by a semi-permeable membrane. In particular, tonicity is
used to describe the osmotic pressure created across a cell
membrane when a cell is exposed to an external solution. Solutes
that can cross the cellular membrane do not contribute to the final
osmotic pressure gradient. Only those dissolved species that do not
cross the cell membrane will contribute to osmotic pressure
differences and thus tonicity. The term "hypertonic", as generally
used herein, refers to a solution with a higher concentration of
solutes than is present on the inside of the cell. When a cell is
immersed into a hypertonic solution, the tendency is for water to
flow out of the cell in order to balance the concentration of the
solutes. The term "hypotonic", as generally used herein, refers to
a solution with a lower concentration of solutes than is present on
the inside of the cell. When a cell is immersed into a hypotonic
solution, water flows into the cell in order to balance the
concentration of the solutes. The term "isotonic", as generally
used herein, refers to a solution wherein the osmotic pressure
gradient across the cell membrane is essentially balanced. An
isotonic formulation is one which has essentially the same osmotic
pressure as human blood. Isotonic formulations will generally have
an osmotic pressure from about 250 to 350 mOsm.
II. Hypotonic Gel-Forming Compositions
[0037] Hypotonic formulations of hydrogel forming polymers,
preferably comprising poloxamers, have been developed for enhanced
delivery through mucus of therapeutic, diagnostic, prophylactic or
other agents, to epithelial tissues. The polymers are administered
at a concentration less than their normal critical gelling
concentration (CGC). A Poloxamer gel administered into the vagina
or colorectum at a concentration equal to or above its CGC will
form a "plug" of gel in the lumen. In contrast, fluid from a
hypotonically-administered Poloxamer solution, where the Poloxamer
is at a concentration below its CGC, will be absorbed into mucosal
tissues, thereby drawing the Poloxamer through the mucus gel toward
the epithelium, thereby enhancing and facilitating delivery of
agents to the body. As water is absorbed into the tissues, the
Poloxamer becomes concentrated and gels near the epithelial tissue
surface, thereby trapping drug molecules in a sustained-release gel
on the tissue surface (rather than, e.g., in a gel that forms
primarily in the lumen as occurs with traditional thermogelling
methods whereby the gelling polymers are administered at a
concentration at or above their CGC). Endogenous mucin
glycopolymers affect the gelling properties of the hypotonic
gelling agents, including the concentration of gelling agent needed
to gel and the pore structure of the resulting gel/mucin mixture.
After vaginal, colorectal, or ocular application, the hypotonic
gelling vehicles coat the epithelium, including the folds or inner
eyelids.
[0038] The examples demonstrate longer vaginal retention of a model
drug administered in a hypotonic gelling agent compared to a bolus
of gel formed in the middle of the vaginal lumen, as would be the
case for a gelling agent administered at the CGC. In the case of
ocular administration, the hypotonic gelling agent forms a uniform
gel coating on the surface of the eye, rather than gelling in a
bolus that is rapidly cleared away by blinking.
[0039] Gel-forming compositions that are capable of forming uniform
gel coatings on epithelial surfaces but do not gel under storage
conditions are described herein. The gel-forming compositions
contain one or more gel-forming polymers in a hypotonic carrier,
optionally containing one or more additional excipients and/or one
or more therapeutic, prophylactic, or diagnostic agents.
[0040] A. Hydrogel-Forming Polymers
[0041] The hypotonic gel-forming compositions contain one or more
gel-forming polymers. Gel-forming polymers are utilized at a
concentration below the normal critical gel concentration (CGC) of
the polymer, e.g. the concentration at which the polymer solution
would gel in a test tube when warmed to 37.degree. C.
[0042] Thermosensitive (aka thermoresponsive) hydrogels are
solutions that undergo sol-gel transitions when the following
criteria are both met:
[0043] 1) at or above the critical gelling concentration (CGC),
and
[0044] 2) at or above the critical gelling temperature.
[0045] Thermosensitive gelling agents (at or above their CGC) used
for biomedical applications are liquid at room temperature, but
form a gel at body temperature. The increase in temperature induces
a rearrangement and alignment of the polymer chains, leading to
gelation into a 3-dimensional structure. This phenomenon is
generally governed by the ratio of hydrophilic to hydrophobic
moieties on the polymer chain. A common characteristic is the
presence of a hydrophobic methyl, ethyl, or propyl group.
Thermosensitive polymers that fit these criteria can be
administered topically in a hypotonic solution at a range of
concentrations that is below its CGC to mucosal tissues to form a
uniform gel coating in vivo.
[0046] Examples of thermosensitive gel formers that can be used
include polyoxyethylene-polyoxypropylene-polyoxyethylene triblock
copolymers such as, but not limited to, those designated by the
CTFA names Poloxamer 407 (CAS 9003-11-6, molecular weight
9,840-14,600 g/mol, percentage of polyoxyethylene by weight
approximately 70%; available from BASF as LUTROL.RTM. F127) and
Poloxamer 188 (CAS 9003-11-6, molecular weight 7680-9510 g/mol,
percentage of polyoxyethylene by weight approximately 80%;
available from BASF as LUTROL.RTM. F68); Poloxamers are also known
by the trade name PLURONIC.RTM. e.g., PLURONIC.RTM. F98 (CAS
9003-11-6, molecular weight 13000 g/mol, percentage of
polyoxyethylene by weight approximately 80%; available from BASF);
Tetronics tetra-functional block copolymers based on ethylene oxide
and propylene oxide available from BASF as TETRONIC.RTM.;
poly(N,N-diethylacrylamide); poly(N,N-dimethylacrylamide);
poly(N-vinylcaprolactam); poly(N-alkylacrylamide);
poly(N-vinylalkylamide); poly(N-isopropyl acrylamide); polyethylene
oxide methacrylate polymers; poly(lactic-co-glycolic acid)
(PLGA)-polyethylene glycol triblock copolymers (PLGA-PEG-PLGA and
PEG-PLGA-PEG); polycaprolactone (PCL)-polyethylene glycol triblock
copolymers (PCL-PEG-PCL and PEG-PCL-PEG); chitosan; and
combinations thereof.
[0047] The hydrogels can be formed from individual gel formers or
as a combination of gel formers. For example, a poloxamer and
another gel former (e.g., a tetronic polymer) may be used in
combination to attain the desired characteristics. In addition,
various forms of the same gel former (e.g., Poloxamer 188 and
Poloxamer 407) can be combined to attain the desired
characteristics.
[0048] The polymer is provided in a concentration less than the
concentration in aqueous solution that forms a gel in a test tube
when heated to 37.degree. C. The concentration must be sufficiently
high, but below the CGC, for the epithelium to absorb enough fluid
for the CGC to be reached in vivo, so gelation can occur
preferentially on/near the mucosal epithelial surface. The range of
time that it takes for gelation to occur depends on the mucosal
surface (the capacity and rate of water absorption), the tonicity
of the solution administered (more hypotonic solutions will drive
more rapid fluid absorption), and the concentration of polymer
administered (if the polymer concentration is too low, not enough
fluid absorption will occur to concentrate the polymer to its CGC).
However, gelation generally occurs within 1 h in the vagina and
colorectum.
[0049] The concentration of the polymer and the presence of
additional components such as the endogenous mucins affect coverage
and rate and degree of gelling. 18% F127 gel mixed with purified
pig gastric mucins (1%) or human cervicovaginal mucus (1:1 ratio)
does not trap virus-sized (.about.100 nm) nanoparticles
(polyethylene glycol coated polystyrene nanoparticles, PSPEG) as
effectively as 18% F127 gel alone. In contrast, 24% F98 gel more
effectively trapped PSPEG particles when mixed with mucins or human
cervicovaginal mucus. However, in vivo viral trapping with
hypotonic gelling agents was more effective at trapping viruses,
including human immunodeficiency virus (HIV, .about.120 nm) and
herpes simplex virus (HSV, .about.180 nm). Administration of
hypotonic solution containing 18% F98, having a CGC of 24%, results
in effective trapping of subsequently administered HIV in the
vagina. Similarly, hypotonic solution containing 10% and 15% F127,
having a CGC of 18%, were also effective in decreasing the MSD of
HIV, indicating trapping. Additionally, both 15% F127 and 18% F98
reduced the diffusion of subsequently administered HSV in mouse
vaginal mucus. The distribution of the individual virus MSD at a
time scale of 1 s illustrated that the trapping (shift to the left)
of the viruses was more uniform in the gel formed by the hypotonic
18% F98 vehicle compared to 15% F127. In additional tests of viral
trapping by hypotonic gelling agents in the colorectum, it was
found that 12% F98 (CGC 24%) did not effectively trap PSPEG
nanoparticles administered 30 mins after the gelling vehicle,
though 18% F98 was effective at trapping PSPEG nanoparticles in the
mouse colorectum. Importantly, these examples illustrate
differences in the gels that form when the hypotonic gelling agents
are administered to different mucosal surfaces, and in this case,
mix with vaginal mucus compared to colorectal mucus prior to
gelling.
[0050] B. Hypotonic Carriers
[0051] The gel-forming compositions include a hypotonic carrier.
The hypotonic carrier will typically be a biocompatible carrier
that preferably causes little to no signs of irritation when
administered to human subjects. The carrier can be naturally
occurring or non-naturally occurring including both synthetic and
semi-synthetic carriers. Preferred carriers are water-based. Other
solutions, including sugar-based (e.g. glucose, mannitol) solutions
and various buffers (phosphate-buffers, tris-buffers, HEPES), may
also be used.
[0052] When hypotonic solutions are applied to an epithelial
surface, a fluid shift occurs and water is moved into the
epithelial tissue. This can cause swelling of the epithelial cells.
In some cases, when the osmotic pressure difference is too large,
the epithelial cells may burst causing tissue irritation or
disruption of the epithelial membrane.
[0053] Hypotonic solution refers to a solution that causes water
absorption by the epithelial surface to which it is administered.
Examples of hypotonic solutions include, but are not limited to,
Tris[hydroxylmethyl]-aminomethane hydrochloride (Tris-HCl, 10-100
mM, pH. 6-8), (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
(HEPES, 10-100 mM, pH 6-8) and dilute solutions of PBS, such as a
solution containing 0.2 grams KCl, 0.2 grams KH.sub.2PO.sub.4, 8
grams NaCl, and 2.16 grams Na.sub.2HPO.sub.4*7H.sub.2O in 1000 ml
H.sub.2O.
[0054] Hypotonic carriers cause dissolved gel-forming polymers to
concentrate at an epithelial surface, resulting in uniform gel
formation on the surface. The hypotonic carrier usually contains
water as the major component. The hypotonic carrier can be water,
although mixtures of water and a water-miscible organic solvent can
also be used. Suitable water-miscible organic solvents include
alcohols, such as ethanol, isopropanol; ketones, such as acetone;
ethers such as dioxane; and esters such as ethyl acetate.
[0055] The hypotonic carrier can be distilled water containing one
or more osmolarity modifying excipients. Sodium chloride is the
excipient that is most frequently used to adjust osmolarity if a
solution is hypotonic. Other excipients used to adjust hypotonic
solutions include glucose, mannitol, glycerol, propylene glycol and
sodium sulfate. Osmolarity modifying excipients can include
pharmaceutically acceptable salts such as sodium chloride, sodium
sulfate, potassium chloride, and other salts to make buffers such
as dibasic sodium phosphate, monobasic potassium phosphate, calcium
chloride, and magnesium sulfate. Other excipients used to adjust
tonicity can include glucose, mannitol, glycerol, or propylene
glycol.
[0056] The hypotonic carrier can have any osmolarity less than the
effective isotonic point (the concentration at which fluid is
neither absorbed nor secreted by the underlying tissues) at that
mucosal surface. The isotonic point varies for different mucosal
surfaces and different buffers, depending on active ion transport
at that epithelial surface; e.g. we have found the isotonic point
in the vagina for sodium-based solutions to be about 300 mOsm/L,
but in the colorectum, it is about 450 mOsm/L. In some embodiments
the solution has a tonicity from 50 mOsm/L to 280 mOsm/L, from 100
mOsm/L to 280 mOsm/L, from 150 mOsm/L to 250 mOsm/L, from 200
mOsm/L to 250 mOsm/L, from 220 mOsm/L to 250 mOsm/L, from 220
mOsm/L to 260 mOsm/L, from 220 mOsm/L to 270 mOsm/L, or from 220
mOsm/L to 280 mOsm/L.
[0057] The hypotonic carrier can include one or more
pharmaceutically acceptable acid, one or more pharmaceutically
acceptable base, or salts thereof. Pharmaceutically acceptable
acids include hydrobromic, hydrochloric, and sulphuric acids, and
organic acids, such as methanesulphonic acids, tartaric acids, and
malcic acids. Pharmaceutically acceptable bases include alkali
metal (e.g. sodium or potassium) and alkali earth metal (e.g.
calcium or magnesium) hydroxides and organic bases such as
pharmaceutically acceptable amines. The hypotonic carrier can
include pharmaceutically acceptable buffers such as citrate buffers
or phosphate buffers.
[0058] C. Additional Agents
[0059] The hypotonic gel-forming compositions can contain one or
more agents to be delivered. Examples include therapeutic agents,
prophylactic agents, diagnostic agents, and/or nutraceuticals. A
biologically active agent is a substance used for the treatment
(e.g., therapeutic agent), prevention (e.g., prophylactic agent),
diagnosis (e.g., diagnostic agent), or to effect a cure or
mitigation of disease or illness, alter the structure or function
of the body, or pro-drugs, which become biologically active or more
active after they have been placed in a predetermined physiological
environment. These may be small-molecule drugs ((e.g., molecular
weight less than 2000, 1500, 1000, 750, or 500 atomic mass units
(amu)), peptides or proteins, sugars or polysaccharides,
nucleotides or oligonucleotides such as aptamers, siRNA, and miRNA,
lipids, glycoproteins, lipoproteins, or combinations thereof.
[0060] The agents can include one or more of those described in
Martindale: The Complete Drug Reference, 37.sup.th Ed.
(Pharmaceutical Press, London, 2011).
[0061] In one embodiment, the agent to be delivered is poorly
soluble in water, but soluble in the carrier containing the gelling
polymer(s). In other embodiment, the agents are water-soluble. Data
also show that benefit is obtained with water soluble drugs, for
example, Brimonidine tartrate, which is soluble up to approximately
1 mg/mL.
[0062] The hypotonic gel-forming formulations can contain a
therapeutically effective amount of a therapeutic agent to treat,
inhibit, or alleviate one or more symptoms of a disease state being
treated. The hypotonic gel-forming compositions can contain an
effective amount of a prophylactic agent to prevent one or more
symptoms of a disease or disorder.
[0063] Agents may be anti-infective (antibiotics, antivirals,
antifungals), for treatment of eye disorders (glaucoma, dry eye),
anti-inflammatories, inhibit neovascularization, fibrosis), for
birth control, for treatment of metabolic disorders, for treatment
of heartburn or ulcers, for treatment of cardiovascular disorders
such as hypertension and atherosclerosis, neuroactive agents, or
chemotherapeutics for treatment of a disease such as cancer.
[0064] Exemplary agents include brinzolamide, cyclosporine A,
brimonidine tartrate, moxifloxacin, budesonide, sunitinib, and
acriflavine.
[0065] Examples of useful proteins include hormones such as
insulin, growth hormones including somatomedins, and reproductive
hormones. Examples of useful drugs include neurotransmitters such
as L-DOPA, antihypertensives or saluretics such as Metolazone from
Searle Pharmaceuticals, carbonic anhydrase inhibitors such as
Acetazolamide from Lederle Pharmaceuticals, insulin like drugs such
as glyburide, a blood glucose lowering drug of the sulfonylurea
class, synthetic hormones such as Android F from Brown
Pharmaceuticals and TESTRED.RTM. (methyltestosterone) from ICN
Pharmaceuticals. Representative anti-proliferative (anti-cancer or
endometriosis) agents include, but are not limited to, alkylating
agents (such as cisplatin, carboplatin, oxaliplatin,
mechlorethamine, cyclophosphamide, chlorambucil, dacarbazine,
lomustine, carmustine, procarbazine, chlorambucil and ifosfamide),
antimetabolites (such as fluorouracil (5-FU), gemcitabine,
methotrexate, cytosine arabinoside, fludarabine, and floxuridine),
antimitotics (including taxanes such as paclitaxel and decetaxel
and vinca alkaloids such as vincristine, vinblastine, vinorelbine,
and vindesine), anthracyclines (including doxorubicin,
daunorubicin, valrubicin, idarubicin, and epirubicin, as well as
actinomycins such as actinomycin D), cytotoxic antibiotics
(including mitomycin, plicamycin, and bleomycin), topoisomerase
inhibitors (including camptothecins such as camptothecin,
irinotecan, and topotecan as well as derivatives of
epipodophyllotoxins such as amsacrine, etoposide, etoposide
phosphate, and teniposide), and combinations thereof. Other
suitable anti-cancer agents include angiogenesis inhibitors
including antibodies to vascular endothelial growth factor (VEGF)
such as bevacizumab (AVASTIN.RTM.), other anti-VEGF compounds;
thalidomide (THALOMID.RTM.) and derivatives thereof such as
lenalidomide (REVLIMID.RTM.); endostatin; angiostatin; receptor
tyrosine kinase (RTK) inhibitors such as sunitinib (SUTENT.RTM.);
tyrosine kinase inhibitors such as sorafenib (NEXAVAR.RTM.),
erlotinib (TARCEVA.RTM.), pazopanib, axitinib, and lapatinib;
transforming growth factor-.alpha. or transforming growth
factor-.beta. inhibitors, and antibodies to the epidermal growth
factor receptor such as panitumumab (VECTIBIX.RTM.) and cetuximab
(ERBITUX.RTM.).
[0066] For imaging, radioactive materials such as Technetium99
(.sup.99mTc) or magnetic materials such as labelled-Fe.sub.2O.sub.3
could be used. Examples of other materials include compounds which
are radioopaque.
III. Methods and Preparations of Hypotonic Gel-Forming
Compositions
[0067] Drug solubilization provides potential advantages that
include enhanced physical stability upon storage, increased drug
penetration into the body, and a more reproducible drug dose when
administered to a patient.
[0068] Water insoluble drugs are especially challenging to deliver
to mucosal surface, such as that of the eye, gastrointestinal
tract, female reproductive tract, airways, etc. due to lack of
absorption. The formulations are particularly suited for delivering
therapeutic agents that are poorly water-soluble. Water-soluble
drugs are also challenging to deliver to a mucosal surface in a
sustained fashion. Thus, the gelling material can also be used as a
vehicle to improve the mucosal delivery of water-soluble drugs by,
for example, providing more sustained drug absorption which can
reduce side effects and provide more prolonged efficacy.
[0069] Further, mucosal surfaces are rapidly cleared and renewed as
a normal defense mechanism from infections and foreign
particulates. Improving drug solubilization can improve mucosal
penetration, and improving distribution, penetration, and retention
of hydrophobic drugs is a promising strategy for improving
therapeutic effects. The following examples demonstrate the
solubilization of various drugs and drug complexes with low water
solubility into materials that also have thermosensitive gelling
properties.
[0070] FIGS. 1-4 depict schemes for achieving direct drug
solubilization of hydrophobic drugs and drug complexes into the
gelling material.
[0071] FIG. 1 is a scheme for solubilization of hydrophobic drugs
(e.g. cyclosporine A or budesonide) by a solvent evaporation
method.
[0072] FIG. 2 is a scheme for solubilization of hydrophobic drugs
(e.g. moxifloxacin) by a bead milling method.
[0073] FIG. 3 is a scheme for solubilization of hydrophobic drugs
(e.g. cyclosporine A or brimonidine) by a dialysis method.
[0074] FIG. 4 is scheme for solubilization of hydrophobic drugs
(e.g. brinzolamide) by a solvent evaporation method.
[0075] Formulations can be prepared as described in the examples
below.
[0076] The formulations can be prepared as liquids for
administration. The gel forming liquid or polymer solubilizes
insoluble drugs by forming micelles. Powder can be made by
freeze-drying and reconstituted at the time of use.
[0077] The formulations may also include pharmaceutically
acceptable diluents, preservatives, solubilizers, stabilizer,
emulsifiers, adjuvants and/or carriers. Stabilizers such as
SPAN.RTM. 20 (sorbitan laurate, CAS Number 1338-39-2) may
facilitate dissolution and prevent re-aggregation. Other exemplary
stabilizers include polysorbates or TWEENS.RTM., e.g., poly-sorbate
20, polysorbate 60, polysorbate 65 and polysorbate 80, and
polyglycerol esters (PGE), polyoxyethylene alkyl ethers, poloxyl
stearates, fatty acids (e.g. oleic acid) and propylene glycol
monostearate (PGMS). In some cases, the composition includes one or
more stabilizers.
[0078] Increased viscosity under no shear may lead to increased
residence time on the mucosal surface of the eye, while shear
thinning when blinking maximizes comfort and lubrication. Thus,
gelling materials with these properties may have favorable
lubricating properties on the surface of the eye while resisting
clearance upon blinking. In some examples, one or more polymer
materials are incorporated into the gelling vehicle for increasing
viscosity under no shear and/or shear thinning when blinking. In
one example, hydroxypropyl methylcellulose (HPMC) is incorporated
into F127 solutions for achieving these desired properties. In some
examples, shear thinning polymers in the concentration range in
which they conventionally demonstrate shear thinning properties are
also included in the composition. Exemplary shear thinning polymers
include cellulose derivatives such as methyl cellulose,
carboxymethylcellulose, hydroxypropyl cellulose, methylcellulose,
etc.
[0079] Dosage formulations will typically be prepared as single or
multiple liquid or dry dosage units in an appropriate applicator. A
person of ordinary skill in the art will be aware of many options
for drug storage and application, such as dual chambered devices
that may be used to keep various components separate during
storage. Multiple dosage units will typically include a barrel
loaded with powder, and a plunger having dosage increments thereon.
These will typically be sterilized and packaged in sealed, sterile
packaging for storage and distribution. See also Remington: The
Science and Practice of Pharmacy, 22nd Edition.
[0080] Dosage unit administrators may be designed to fit the
anatomic location to which drug is to be delivered, such as
intrarectally, intravaginally, intranasally, or intrabuccally.
IV. Methods of Administering Hypotonic Gel-Forming Compositions
[0081] The hypotonic gel-forming compositions can, in principal, be
applied to any water-absorbent surface, including skin as well as
mucosal tissues, to form a gel. Preferably, the formulations are
applied as a liquid to a mucosal coating on an epithelial surface
of a subject in need of a therapeutic, prophylactic, diagnostic, or
nutritional effect. The gel-forming composition can be applied in
any number of ways known to the skilled artisan as long as the
hypotonic solution, or reagents forming the hypotonic solution,
contacts the surface.
[0082] By applying the gel-forming compositions as a hypotonic
formulation, water is absorbed into the epithelial tissue. Water
absorption provides for concentration of the gel-forming polymer at
the surface, resulting in uniform gel formation at the surface. The
gel can act as a barrier, reservoir, or combination thereof. Agents
or excipients in the gel-forming composition can become entrapped
in the gel and can be released at or into the surface.
[0083] Epithelial surfaces include oral surfaces, pharyngeal
surfaces, esophageal surfaces, pulmonary surfaces, ocular surfaces,
aural surfaces, nasal surfaces, buccal surfaces, lingual surfaces,
vaginal surfaces, cervical surfaces, genitourinary surfaces,
alimentary surfaces, anorectal surfaces, and/or skin surfaces.
[0084] In some examples, the hypotonic gel-forming compositions
retain an effective concentration of one or more active agents at
one or more mucosal surfaces for an extended period of time, for
example, more than 6 hours, more than 12 hours, more than 1 day,
more than 2 days, more than 3 days, more than 4 days, more than 5
days, more than 6 days, or more than a week.
[0085] In some cases, the hypotonic gel-forming compositions
increase the concentration of one or more active agents at or near
the site of application by 2-fold, 3-fold, 4-fold, 5-fold, 6-fold,
7-fold, 8-fold, 9-fold, 10-fold, or more than 10-fold compared to
active agents delivered without gel-forming vehicles, for example,
in saline solution. When the hypotonic gel-forming compositions are
applied to the eye, the mucosal sites with increased concentration
of active agents include one or more of cornea, aqueous humor,
sclera, conjunctiva, iris, lens, retina, and retinal pigment
epithelium.
[0086] In some examples, the hypotonic gel-forming compositions
deliver active agents (e.g., acriflavine and sunitinib malate) to
retina and/or choroid in an amount effective to reduce retinal
and/or choroidal neovascularization by 10%, 20%, 30%, 40%, 50%, or
more than 50% compared to active agents delivered without
gel-forming vehicles, for example, in saline solution.
[0087] In other examples, the hypotonic gel-forming compositions
deliver active neuroprotective agents (e.g., sunitinib malate) to
the retina in an amount effective to increase the survival of
retinal ganglion cells following optic nerve injury, and/or to
increase the expression of .gamma.-synuclein and/or 0111 tubulin in
retinal ganglion cells following optic nerve injury by 2-fold,
3-fold, 4-fold, 5-fold, or more than 5-fold compared to active
agents delivered without gel-forming vehicles, for example, in
saline solution.
[0088] In further examples, the hypotonic gel-forming compositions
deliver active agents (e.g., brinzolamide) to the eye in an amount
effective to lower intraocular pressure (IOP) by 10%, 20%, 30%,
40%, 50%, or more than 50% compared to those delivered without
gel-forming vehicles, for example, in saline solution within less
than 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, or 24
hours.
[0089] In other examples, the hypotonic gel-forming compositions
deliver active agents (e.g., Cyclosporine A) to the eye in an
amount effective to increase tear production by 10%, 20%, 30%, 40%,
50%, or more than 50% compared to those delivered without
gel-forming vehicles, for example, in saline solution within less
than 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, or 24
hours.
[0090] The present invention will be further understood by
reference to the following non-limiting examples.
EXAMPLES
Example 1: Cyclosporine a Eye Drops
[0091] Rapid drug elimination from the ocular surface is a major
obstacle for topical drug delivery, and as a result, many eye drops
are prescribed for several times daily application.
[0092] Materials and Methods
[0093] The first example embodies the solubilization of
cyclosporine A (used for dry eye) in the thermosensitive gelling
vehicle (gelCsA) prepared using the method shown schematically in
FIG. 3. Cyclosporine A and Pluronic F127 (10-18% w/w) were
co-dissolved in DMSO and dialyzed against water balanced with salts
(sodium chloride, final osmolality 200 mOsm) for 2 days to remove
DMSO. CsA concentration in all the formulations were 0.05%. Tear
production was measured using Schirmer's strips held in contact
with the ocular surface. Drug concentrations were measured using
LC-MS.
[0094] Results
[0095] It has been reported in the literature that cyclosporine
increases tear production in healthy animal eyes. FIG. 5A shows
cumulative increase in tear production induced by cyclosporine in
healthy rabbit eyes for 12 h after a single drop of Cyclosporine A
formulated in various concentrations of Pluronic F127 including
10%, 12%, 15%, and 18% w/w. The hypotonic 12% F127 vehicle for
cyclosporine provided the largest increase in tear production.
[0096] FIG. 5B shows a graph of the tear production in the healthy
rabbit eye 10 h after each of 5 daily doses of gelCsA, the gel
vehicle (containing no drugs), RESTASIS.RTM., the RESTASIS.RTM.
vehicle (Refresh Endura), or no treatment (Untreated). Only in the
case of gelCsA is an increase in tear production due to
cyclosporine delivery observed 10 h after eye drops were dosed.
This further demonstrates the potential for gelCsA to be dosed once
per day, whereas RESTASIS.RTM. is prescribed twice per day.
[0097] FIGS. 5C and D show cyclosporine levels in rat cornea and
conjunctiva tissue after administering various cyclosporine eye
drops, demonstrating that the hypotonic gelCsA provides superior
cyclosporine delivery compared to the isotonic and conventional
gelling vehicles, as well as RESTASIS.RTM..
Example 2: Brinzolamide Drops for Glaucoma Therapy
[0098] Materials and Methods
[0099] Brinzolamide is used to lower intraocular pressure (IOP) as
a glaucoma therapy. Brinzolamide was formulated in the gelling
vehicle (gelBRZ) using the method of FIG. 4. Pluronic F127 ranged
from 10-18% and salts were added to adjust osmolality up to
isotonic (300 mOsm/kg) when required. The effect of the vehicle
itself (gelBRZ vehicle) and brinzolamide drops on IOP in
normotensive rabbits was tested after administering single eye drop
with 50 uL at 10 mg/mL.
[0100] Results
[0101] FIG. 6A is a graph showing the gelBRZ formulated as either a
conventional (18% F127) gelling material, or at the lower
concentration (12% F127) formulated to be either hypotonic or
isotonic. FIG. 6B shows that the gelBRZ vehicle had no effect on
IOP of the treated or contralateral eye in normotensive rabbits. It
further compares the hypotonic gelBRZ formulation to the commercial
eye drop, AZOPT.RTM. (a clinical brinzolamide ophthalmic suspension
of 1% brinzolamide). A single dose of 1% brinzolamide had a more
pronounced effect on IOP lowering for up to 8 h after treatment
when delivered as gelBRZ (12%, hypotonic) compared to AZOPT.RTM..
Further, hypotonic gelBRZ (35 mOsm) lowered IOP more than isotonic
gelBRZ (300 mOsm) at early time points up to 4 h.
Example 3: Brimonidine Tartrate Ophthalmic Formulation
[0102] Materials and Methods
[0103] Brimonidine tartrate is a water-soluble drug that can be
directly dissolved into the gelling vehicle (gelBT). It was first
tested whether there was an optimal F127 concentration for
administering the brimonidine tartrate in a hypotonic gelling
vehicle to the eye, as measured by reduction in IOP in normotensive
rabbits. IOP reduction was then compared for F127 concentrations
ranging from 12-18% in hypotonic (no salt) and isotonic (salt to
adjust to 300 mOsm/kg) in normotensive rabbits. Drug concentrations
were measured by LC-MS.
[0104] Results
[0105] FIG. 7A shows the cumulative change in IOP over 8 h after
administration of brimonidine tartrate 0.15% in F127 (10-18%)
(gelBT). The cumulative decrease in IOP in normotensive rabbits
over 8 h after a single drop of hypotonic gelBT was highest for
gelBT containing 12% F127. FIG. 7B shows hypotonic gelBT was more
effective in lowering IOP in normotensive rabbits over an 8 h
period compared to isotonic (12% F127) and conventional (18% F127)
eye drops. FIG. 7C shows the gelBT vehicle had no effect on IOP,
and hypotonic gelBT was more effective than the commercial Alphagan
eye drop at lowering IOP over 8 h. Figures D-F show BT levels in
cornea, conjunctiva, and aqueous from rats 1, 4, and 8 h after the
last dose (dosing 2.times. daily for 5 days). Drug levels were
higher for hypotonic gelBT than all other formulations. FIG. 7G
shows that even a mild hypotonicity (200 mOsm) was as effective in
lowering IOP for gelBT.
Example 4: Incorporation of Polymer Materials into Gelling
Vehicle
[0106] Materials and Methods
[0107] Polymer materials were incorporated into the gelling
vehicle, hydroxypropyl methylcellulose (HPMC) into F127 solutions,
for shear thinning properties, which can be advantageous in the
case of blinking (ocular administration) or lubrication (rectal
administration). It also may increase the viscosity of the gel at
rest (under no shear) and improve the retention time at mucosal
surfaces.
[0108] Results
[0109] As shown in FIG. 8A, addition of 0.5% HPMC to F127 increases
the viscosity under low/no shear, which is already thousands-fold
higher than a standard lubricating eye drop (GENTEAL.RTM.). FIG. 8B
shows that the shear thinning properties (decrease in viscosity
when placed under shear) are similar for F127 solutions containing
HPMC compared to standard lubricating eye drops (GENTEAL.RTM.).
Thus, addition of hydroxypropyl methylcellulose (HPMC) to F127
solutions increases the viscosity under low/no shear, while
maintaining the low viscosity observed in standard lubricating eye
drops (e.g. GENTEAL.RTM.) under high shear (similar to shear rate
when blinking).
[0110] Increased viscosity under no shear may lead to increased
residence time on the mucosal surface of the eye, while shear
thinning when blinking maximizes comfort and lubrication. Thus,
such gelling materials may have favorable lubricating properties on
the surface of the eye while resisting clearance upon blinking.
Materials include shear thinning polymers in the concentration
range in which they conventionally demonstrate shear thinning
properties, such as cellulose derivatives including methyl
cellulose, carboxymethylcellulose, hydroxypropyl cellulose,
methylcellulose, etc.
Example 5: No Ocular Irritation in the Presence of Hypotonic
Gelling Vehicles with Different Osmolalities
[0111] New Zealand white rabbits were dosed topically with 50 uL
per eye drop twice per day for 5 weeks to assess potential ocular
irritation. Test agents included 12% F127 solutions containing
sodium chloride to produce final osmolalities ranging from no added
salt up to 300 mOsm/kg. The negative control was balanced salt
solution (BSS), and there was a group a animals receiving no
treatment. There was no difference in corneal staining (lisamine
green 1%) or blink rate (number of blinks in 3 min) for any
formulation compared to untreated animals.
Example 6: Drug Delivery to Retina/Choroid Through Topical
Administration
[0112] C57/B6 mice where used to test the topical delivery of
sunitinib malate (5 uL at 4 mg/mL) and acriflavine (5 uL at 5
mg/mL) in preventing choroidal neovascularization (CNV) in mice
after laser induced rupture of Bruch's membrane in three locations.
After laser, both drugs either dissolved in 12% F127 or a aqueous
vehicle control (saline or water), were dosed daily for 7 days.
Only the formulations containing 12% F127 were efficacious in
suppressing neovascularization in the choroid.
Example 7: Melanin-Binding Prolonged Therapeutic Effects of
Topically Dosed Sunitinib in Hypotonic Gelling Vehicle Following
Optical Nerve Injury
[0113] Rats were dosed topically with sunitinib malate (5 uL at 4
mg/mL) in 12% F127 daily for 5 days unilaterally. Then, the optic
nerve head was exposed and crushed unilaterally and the
contralateral eye was used as the control for comparison. 14 days
after crushing the nerve (without additional topical dosing), the
tissues were isolated for qPCR for genes expressed by retinal
ganglion cells (RGCs). This dosing scheme led to protection of RGCs
in pigmented rats (Brown Norway) and not non-pigmented rats
(Wistar), suggesting that binding to melanin in the eye led to a
prolonged therapeutic effect.
Example 8: Treatment Using Hypotonic Gelling Vehicle in Optical
Nerve Injury
[0114] Pigmented rats (Brown Norway) were dosed topically (5 uL at
4 mg/mL) with sunitinib malate in 12% F127 or in saline once weekly
unilaterally. The optic nerve head was exposed and crushed
unilaterally on Day 8 and the contralateral eye was used as the
control for comparison. 14 days after crushing the nerve (Day 22),
the tissues were isolated for qPCR for genes expressed by retinal
ganglion cells (RGCs). Protection of RGCs was only observed when
sunitinib malate was dosed in 12% F127, but not when sunitinib
malate was dosed in saline.
Example 9: Ocular Tissue Distribution of Therapeutic Agents
Delivered in Hypotonic Gelling Vehicles
[0115] Materials and Methods
[0116] Sunitnib malate was dissolved in 12% F127 at a concentration
of 4 mg/ml and dosed topically to pigmented (Dutch belted) rabbits
and pigmented pigs (juvenile farm pigs) once per day for a total of
14 days or 5 days, respectively. Dosing in both rabbits and pigs
occurred without anesthesia and 50 uL or 50-100 uL of an eye drop
was administered, respectively. However, dosing in pigs occurred
while distracted with food. Tissues were collected 6 h after the
final dose for rabbits and 1 h after the final dose for pigs. The
drug concentrations were measured by LC-MS.
[0117] Results
[0118] Sunitinib malate was dosed topically in the hypotonic
gelling vehicle was dosed topically to (FIG. 9A) dutch belted
rabbits daily for 14 days and (FIG. 9B) farm pigs daily for 5 days.
Tissues were isolated and sunitinib and primary metabolite
(N-desethyl sunitinib) levels quantified in various ocular tissues
and fluids. Therapeutically relevant levels of drug were found in
the anterior and posterior segments.
[0119] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
skill in the art to which the disclosed invention belongs.
Publications cited herein and the materials for which they are
cited are specifically incorporated by reference.
[0120] Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. Such equivalents are intended to be encompassed by the
following claims.
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